Peripheral Blood CD56dim Research Articles

Immunophenotypic, cytotoxic, proteomic and genomic characterization of human cord blood vs. peripheral blood CD56Dim NK cells.

Unrelated cord blood (CB) is an excellent alternative as an allogeneic donor source for stem cell transplantation. CB transplantation is associated with lower incidence of severe acute graft versus host disease (GVHD) and chronic GVHD but similar rates of malignant relapse compared with other unrelated donor cell transplants. NK cells are critical innate immune components and the comparison of CB vs. peripheral blood (PB) NK cells is relatively unknown. NK cell receptor expression, cell function, and maturation may play a role in the risk of relapse after CB transplant. We investigated CB vs. PB NK cell subset cytotoxicity, function, receptor expression, and genomic and proteomic signatures. The CB CD56dim compared with PB CD56dim demonstrated significantly increased expression of NKG2A and NKG2D, respectively. CB vs. PB CD56dim NK cells had significantly decreased in vitro cytotoxicity against a variety of non-Hodgkin lymphoma targets. Various proteins were significantly under- and over-expressed in CB vs. PB CD56dim NK cells. Microarray analyses and qRT-PCR in CB vs. PB CD56dim demonstrated significantly increased expression of genes in cell regulation and development of apoptosis, respectively. In summary, CB vs. PB CD56dim NK cells appear to be earlier in development, have decreased functional activity, and increased capacity for programmed cell death, suggesting that CB NK cells require functional and maturational stimulation to achieve similar functional levels as PB CD56dim NK cells.

Distinguishing Human Peripheral Blood NK Cells from CD56dimCD16dimCD69+CD103+ Resident Nasal Mucosal Lavage Fluid Cells

Natural killer (NK) cells are members of the innate lymphoid cells group 1 (ILC1s), which play a critical role in innate host defense against viruses and malignancies. While many studies have examined the role of circulating peripheral blood (PB) CD56+ NK cells, little is known about the resident CD56+ cell population. Therefore, matched CD56+ cells from nasal lavage fluid (NLF) and PB of smokers and non-smokers were compared phenotypically, via flow cytometry, and functionally, via NK-cell specific gene expression. NLF and PB CD56+ cells had similar expression of CD56, but differentially expressed tissue residency (CD69 and CD103) and cytotoxicity (CD16) markers. In addition, NLF CD56dim cells expressed lower levels of cytotoxicity-associated genes, perforin (PRF1) and granzyme B (GZMB), and increased levels of cytokines and cell signaling molecules, TRAIL, IFNGR2, and IL8, as compared to PB CD56dim cells. In smokers, ITGA2 was downregulated in NLF CD56dim cells, while markers of cytotoxic function were primarily downregulated in PB CD56dim NK cells. Overall, NLF CD56dim cells are a unique cell population that likely play a role in orchestrating innate immune responses in the nasal cavity, which is distinct from their role as a non-antigen-restricted cytotoxic CD56dim lymphocytes in the PB.

Soluble HLA-G dampens CD94/NKG2A expression and function and differentially modulates chemotaxis and cytokine and chemokine secretion in CD56bright and CD56dim NK cells

AbstractSoluble HLA-G (sHLA-G) inhibits natural killer (NK) cell functions. Here, we investigated sHLA-G–mediated modulation of (1) chemokine receptor and NK receptor expression and function and (2) cytokine and chemokine secretion in CD56bright and CD56dim NK cells. sHLA-G-treated or untreated peripheral blood (PB) and tonsil NK cells were analyzed for chemokine receptor and NK receptor expression by flow cytometry. sHLA-G down-modulated (1) CXCR3 on PB and tonsil CD56bright and CD56dim, (2) CCR2 on PB and tonsil CD56bright, (3) CX3CR1 on PB CD56dim, (4) CXCR5 on tonsil CD56dim, and (5) CD94/NKG2A on PB and tonsil CD56bright and CD56dim NK cells. Such sHLA-G–mediated down-modulations were reverted by adding anti–HLA-G or anti–ILT2 mAbs. sHLA-G inhibited chemotaxis of (1) PB NK cells toward CXCL10, CXCL11, and CX3CL1 and (2) PB CD56bright NK cells toward CCL2 and CXCL10. IFN-γ secretion induced by NKp46 engagement was inhibited by NKG2A engagement in untreated but not in sHLA-G–treated NK cells. sHLA-G up-regulated secretion of (1) CCL22 in CD56bright and CD56dim and (2) CCL2, CCL8, and CXCL2-CXCL3 in CD56dim PB NK cells. Signal transduction experiments showed sHLA-G–mediated down-modulation of Stat5 phosphorylation in PB NK cells. In conclusion, our data delineated novel mechanisms of sHLA-G–mediated inhibition of NK-cell functions.

NK Receptor (NKR)-Mediated Signaling Pathways in Cord Blood (CB) CD56dim Versus Peripheral Blood (PB) CD56dim NK Cells: Implication for Immaturity in Cord Blood NK CD56dim Innate Immunity

Background: NK cells are characterized by absent CD3 but expression of CD56dim (90%, cytotoxic) and CD56bright (10%, mediator). NK cells may contribute to the immaturity in cord blood innate and adaptive immunity, and play an important role in the GVL effect post CBT. However, little is known regarding the NKR signaling pathways in CB vs PB CD56dim NK cells and its relationship to the cytotoxic activity. We previously demonstrated the ability to ex-vivo expand CB into NK subsets with profound NK in-vitro and in-vivo cytotoxic activity (Ayello/Cairo BBMT 2006). We further observed that there were 33 and 37 proteins over and under expressed by proteomic expression profiling studies of CB vs PB CD56dim (Shereck/Cairo, ASH 2007; ASPHO 2007; AACR 2007). The differential protein expressions included NKG2A, IP3R type 3, NCR3, MAPKAPK5, Notch 2, PLEK, and NF-X1 using both immunophenotype and proteomic profiling studies.Objectives: To understand the importance of NKR signaling pathways in mediating the differential protein expression and thus in regulating the NK cytotoxic activities in CB vs PB CD56dim, we compared the genomic expression pattern in CB vs PB CD56dim.Methods: For CD56dim isolation, first, NK cells were isolated indirectly by magnetic separation from non-NK cells. Second, the pre-enriched NK cells (CD56+/CD3−) from CB and PB were directly labeled with CD16 (FCGR3) MicroBeads, and the CD56+ CD16+ NK cells (CD56dim) were eluted after removing the column from the magnetic field (Miltenyi). Purity of CD56dim NK cells were then examined by flow cytometry (BD FACScan). For genomic studies, total RNA was isolated and reverse transcribed to cDNA using T7-Oligo (dT) primer. cRNA was Biotin-labeled by in vitro transcription. Fragmented biotin-labeled cRNA was hybridized to GeneChip U133A_2 in GCOS-operated Fluidics Station 450, and then scanned by GeneChip Scanner 3000 (Affymetrix). Data were analyzed using Agilent GeneSpring. Signal intensities were compared using one way ANOVA and Welch Test for statistical analysis.Results: There were 193 and 222 genes over and under expressed at the genomic level between CB vs PB CD56dim NK cells, respectively. CB vs PB CD56dim significantly overexpressed NKG2A (2.14F), CD16b (2.46F), KIR2D (2.13F), NKp44 (NCR2; 2.62F), PBX1 (4.29F), ENPEP (3.93F). There was no significant difference in NKR gene expression of CD16a, CD161, NKG2C, and NKp46 in CB vs PB CD56dim. CB vs PB CD56dim underexpressed the following NK genes: IP3R (1.32F), MAPKAPK5 (1.77F), NCR3 (1.24F), ACACB (3.23F), BBS1 (2.00F).Conclusion: CB vs PB CD56dim overexpressed NKG2A, CD16b, KIR2D, and NKp44 genes compared to only NKG2A was overexpressed at the protein level. These results suggest that NKR protein product levels in CB CD56dim may be directly regulated at the translation level, but not the transcription level. The discrepancy of IP3R, ENPEP, PBX1, and MAPKAPK5 gene expression suggest the involvements of IP3 and calcium ions in NKR signaling pathways. Since the Notch2, PLEK, and NF-X1 gene expression patterns were not increased, the augmented protein levels may result from the regulation of protein translation. The potential regulators of this process may include PBX1, ENPEP, ACACB, and BBS1 though the roles of these regulators need to be defined. We conclude that genomic differences between CB vs PB CD56dim may play an important role in regulating NKR signaling pathway, and thus contribute to disparate cytotoxic activity between CB vs PB and suggest a possible explanation for immaturity of cord blood innate and adaptive immunity.

Immunophenotypic and Proteomic Characterization of Cord Blood (CB) CD56dim Versus Peripheral Blood (PB) CD56dim NK Cells.

Background: Neonates may succumb to serious infection due to deficiencies in adaptive cellular immunity, however, little is known regarding the immaturity of CB NK cell innate immunity (Satwani/Cairo et al Biol Neonate 2005). NK cells are characterized by absent CD3 but expression of CD56dim (90%, cytotoxic) and CD56brigh t (10%, mediator) (Shankaran et al Nature 2001). NK subsets' function is based on their repertoire of NK receptors (NKRs) (Moretta et al Annu Rev Immunol 2001). Furthermore, the amount of CB NK cells is significantly low in cryopreserved CB for CBT (Cairo et al Transfusion 2005), however, they may play an important role in the graft vs leukemia (GVL) effect post CBT. We recently demonstrated the ability to expand CB into NK phenotype ex-vivo with profound NK cytotoxic activity (Ayello/Cairo et al BBMT 2006).Objectives: To characterize and compare CB vs. PB NK CD56dim NKR and protein expression.Methods: We positively selected CB vs. PB CD56+ cells using immunomagnetic beads (Miltenyi) and sorted into CD3−/CD56bright and CD3−/CD56dim subsets. NKR expression was evaluated using CD16, CD158a {KIR2DL1}, CD158a,h {KIR2DL1 and KIR2DS1}, CD158b {KIR2DL2}, CD161, NKG2A, NKG2C, NKG2D, Nkp44, NKp46. Additionally, quantitative proteomic analysis was performed using extracts of CB and PB CD56Dim cells using cleavable ICAT labeling followed by multi-dimensional liquid chromatography and tandem mass spectrometry (MS/MS) (Lim et al Lab Invest 2004).Results: CB vs. PB CD56dim showed significant increased expression of NKG2A (81.34 ± 1.51 vs. 54.09 ± 4.56, p < 0.03) and NKG2D (94.08 ± 2.36 vs. 77.43 ± 3.93, p < 0.035). There was no significant difference in NKR expression of CD16, KIR2DL1, KIR2DS1, KIR2DL2, CD161, NKG2C, Nkp44, and NKp46 seen in CB vs. PB CD56dim. CB CD56dim vs. CD56bright had significant increased expression of FcgrIII (91.17 ± 1.95 vs. 28.73 ± 11.23, p < 0.03) and KIR2DL2 (31.88 ± 4.39 vs. 3.08 ± 0.99, p < 0.02). Furthermore, there were 33 and 37 proteins over and under expressed by ≥ 2 fold between CB vs. PB CD56dim NK cells, respectively. CB CD56dim overexpressed functional proteins were 46% binding, 17% catalytic, 15% signaling, 15% transcription, 3% enzyme, 2% structural, and 2% transport. CB CD56dim underexpressed Inositol 1,4,5-triphosphate receptor type 3, mitogen-activated protein kinase 5, and natural cytotoxicity triggering receptor 3 precursor by 8.33, 6.67, and 2.5 fold decrease, respectively. CB CD56dim overexpressed neurogenic locus notch homolog protein 2 precursor, pleckstrin homology domain-containing family A member 1, and transcriptional repressor NF-X1 by 16.67, 7.14, and 5.26 fold increase, respectively.Conclusion: While there are many similiarities in CB vs. PB CD56dim, CB CD56dim appear to be quite mature in development compared to other CB immune cell subsets and in fact have overexpression of a significant number of proteins including NKG2D, NKG2A, and several (33) important functional proteins. These studies suggest that CB CD56dim NK cells are similar in development to PB CD56dim NK cells and may contribute to the GVL effect post UCBT.

Peripheral Blood (PB) CD56bright and CD56dim Do Not Exhibit Differences in NKR Expression Compared to Their Cord Blood (CB) Counterparts: CB CD56dim May Represent an Intermediary between CB CD56bright and PB CD56dim.

NK cells are characterized by absent CD3 and expression of CD56. CD56 NK cells are classified into CD56dim (90%) that are primarily cytotoxic, and CD56bright that secrete cytokines (Kaplan et al PNAS 1998; Shankaran et al Nature 2001). NK subsets carry out their respective functions based on their repertoire of NK receptors (NKRs), both activating and inhibiting (Moretta et al Annu Rev Immunol 2001). PB CD56dim cells express high concentrations of killer-cell immunoglobulin receptors (KIR) and C-type lectin receptors. PB CD56bright NK cells have increased expression of C-type lectin receptors, but have low expression of the KIRs (Nagler J. Immunol 1989). CD16 (the Fcγ receptor III or FcγRIII) which is responsible for binding to antibody-coated targets and initiating antibody-dependent cellular cytotoxicity (ADCC) has increased expression in CD56dim vs CD56bright NK cells (Leibson et al Immunity 1997). While the characterization and function of PB NK subsets and NKR expression are well described, there is little information regarding CB NK subsets and NKRs. We previously demonstrated a significant increase in CB NK NKR expression in ex-vivo engineered CB MNC following 48 hours of induction with IL-2, IL-7, IL-12, and Anti-CD3 (Ayello/Cairo et al BBMT 2006). In this study, we compared PB vs. CB NK subsets and NKR expression. PB and CB cells were positively selected for CD56+ using CD56 magnetic beads (Miltenyi, Aubrun, CA). CD56+ cells were sorted into CD3−/CD56bright and CD3−/CD56dim subsets by FACS sorter and NK receptor expression (CD16, CD158a {KIR2DL1} CD158a, h {KIR2DL1 and KIR2DS1}, CD158b {KIR2DL2}, CD161, NKG2A, NKG2C, NKG2D, Nkp44, NKp46, Becton Dickinson, Mountainview, CA,) of each subset was analyzed by flow cytometry. CD56+ selection yielded >89% purity (PB-96%, CB-89%). There was no statistical difference (mean ± SEM) in the receptor expression between the CB CD56bright and PB CD56bright and also between the CB CD56dim and PB CD56dim. However, PB CD56bright vs. PB CD56dim had increased expression of NKG2A (93.28 ± 2.83 vs. 66.64 ±7.74, p< 0.015), NKG2C (62.11 ±11.79 vs. 8.08 ± 2.98, p< 0.12), NKp44 (61.52 ±10.35 vs. 3.79 ± 2.32, p< 0.005) and NKp46 (92.53 ±3.31 vs. 64.66 ± 12.34, p< 0.05). PB CD56dim had increased expression of CD16 (93.30 ± 2.71 vs. 61.15 ± 11.79, p< 0.07) compared to PB CD56bright. The CB CD56dim compared to CB CD56bright has increased CD16 expression (85.06 ± 6.75 vs. 40.91 ± 5.74, p< 0.004) only. The PB CD56bright only differed from the CB CD56dim with respect to NKp44 (p< 0.021). The CB CD56bright differed from the PB CD56dim with respect to KIR2DL1 (p< 0.026), CD161 (p < 0.05), NKG2A (p < 0.025), and NKG2C (p < 0.05). In conclusion, there does appear to be a definite difference in NKR expression in PB CD56bright vs. PB CD56dim. However, PB vs. CB CD56dim and PB vs. CB CD56bright did not have any statistically significant NKR expression differences suggesting that the subsets have similar phenotypes in their respective cell source. Based on these results, we postulate that the CB CD56dim subset might reflect an intermediary step in development transitioning from CB CD56bright to PB CD56dim.